Production of alkylcycloparaffins



portance in recent years. thermoplastic polymer of ethylene, is producedon an .able properties thereto.

nited States Patent No Drawing. Application;ctober:26, 1950,

Serial .N0.'=1 92,370

8 Claims. *(Cl. 260- 666) This application vis a icontinuation-in-partof my co- .pending application Serial No. 673,612, filed May 31,

1946, 'now abandoned.

This invention relates to the productionof 'alkylcyclw paraifins. It ismore specifically :concerned with the catalytic condensation of ethyleneand =cyclopara'fiins.

The polymerization-of ethylene has assumed great'im- For example,Polythene, a

extensive scale by the polymerization of ethylene at extremely highpressures. Likewise, lubricating -*oils with high viscosity indices havebeenmanufactured commercially by-polymerizing ethylene in the presenceof aluminum chloride. In general the processes.heretofore'used have beencharacterized by low-yields, by high pressures,

and, frequently, by hig'h catalyst consumption. "I have discovered amethod-of producing valuable products "containing a plurality ofethylene radicals by a -process in which these disadvantages have beenlargely overcome. My process employs relatively low pressure *andproduces high yields of product per unit weight ofcatalyst. Although myproducts are produced primarily 'by' the condensation of ethylene, theyalso contain a cycloparafiin ring in each molecule, which impartsunusual'and valu- In a broad aspect my invention relates to *thereaction of ethylene in thepresence of an organic peroxide and. a

In one embodiment my invention relates to a process for producingalkylcycloparaffins which comprises .subjecting ethylene to the action"of an organic peroxide condensation catalyst at condensation conditionsin thepresenceof a diluent comprising a'cycloparaflin.

In a more specific embodimentmy invention relates to a process forproducingalkylcycloparaffins which comprises subjecting ethylene to theaction of an organic peroxide condensation catalystat apressure aboveabout atmospheres, a temperature at least as high as the initialdecomposition temperature vof said catalyst, and in the presence ofadiluent compris'ing a cycloparaflin containing at least;five:carbonatoms in the ring.

I. have found that when :ethlyene 'is contacted with an organic peroxidein the presence of a diluent comprising a naphthene or cycloparaffin,particularly one containing five or more carbon atoms in the ringyunderthe conditions herein specified, that such 'diluent is not inert butactually enters into the reaction as evidenced by the fact that thepolymer product contains onemolecule of cycloparafiin in each molecule.of the polymer. The manner in which the reaction'takes place is believedto be as follows:

Hz Hz The cyclohexyl .radical formed instep 4' starts a new cycle as'instep 3. That the solvent or diluent does react was proved by 'bothanalysis of lower molecular weight condensation products as well asbyshowing that the diluentis actually consumed during the course of thereaction. 7

The reacting of the cyelopara'ffin diluent in the manner shown. appearsto be the reason why the products produced by .the present process .areliquids or grease-like polymers in contradistinction to the waxes orhard solid polymers produced by the .prior art processes. Thegrease-like, semi-solid polymers produced in my process are particularlyuseful in electrical applications because of their highdi-electricstrengthand because, unlike the hard, solid ethylene polymersproduced in the prior art processes, they do not crack when subjected torapid fluctuations in temperatures. The products produced in my processare also valuable as pour point depressants and viscosityindexirnproversffor lubricating oils. The ethylene polymers lheretoforeproduced, even those employing a paraffin as .a diluent, do ,notact as:pour point depressants .or viscosity index improvers. .In addition, thealkylcycloparai'lins that I produce may be-dehydrm genated to alkylaromatics, which are easily convertible to surface active agents bysulfonation and neutraliza- 'tion, and theilike.

The diluent used .in the present process comprises a nap'htheneor acyeloparafiin and preferably those containing at :least 'five. carbonatoms in the ring. Naphthenes or cycloparaflins containing less than.five carbon atoms in the ring possess less stability and frequentlyundergoring splitting during the course of the reaction. Preferredcycloparafiins comprise cyclohexanes such as cyclohexane .andalkylcyclohexanes including methylcyclohexane; and 'cyclopentanesincluding particularly alkylcyclopentanes such as methylcyc'lopentane.Other types of cycloparafiins that may be used as diluents, in myprocess include deczihydronaphthalene and bicycle (2.2.1) heptane.Products of somewhat diflerent characteristics may be obtained byemploying cycloparaffin diluents containing one or two halogen atomsattached to the ring; preferably the halogen atoms comprise chlorine orfluorine.

I am aware that certain substances, such as benzene, toluene, andmethanol have been suggested as solvents for this reaction. However, theuse of cycloparafiins, as hereinbefore stated, results in the productionof alkylcycloparaflins having relatively long side chains and, inaddition, gives unexpectedly better yields than the compounds suggestedand makes possible the polymerization or condensation of ethylene atlower temperatures and pressures than usually are possible with thearomatic or alcoholic solvents.

The catalysts that may be used in the present process comprise organicperoxides that catalyze the polymerization or condensation of ethylene.These substances include peracetic acid, diacetyl peroxide, toluic acidperoxide, oleic peroxide, benzoyl peroxide, tertiary butyl perbenzoate,di-tertiary butyl peroxide, hexyl peroxide, and methylcyclohexylhydroperoxide.

The process of my invention may be carried out in batch operation byplacing a quantity of the eycloparaffinic diluent and the catalyst in areactor equipped with a mixing device, adding the ethylene, heating to areaction temperature while mixing the contents of the reactor, coolingafter a suitable period of time, and recovering the polymer orcondensation product.

The preferred method of operation is of the continuous type. In thismethod of operation the ethylene, diluent, and catalysts arecontinuously charged to a reactor maintained under suitable conditionsof temperature and pressure. The reactor may be an unpacked vessel or itmay contain an adsorbent packing material, such as fire brick, alumina,dehydrated bauxite, and the like, upon which the catalyst is depositedand retained. The polymer is separated from the reactor efiluent. Thediluent and unconverted ethylene may be recycled to the reaction zone.The reaction temperature can be controlled to an appreciable degree byadjusting the amount of diluent charged to the process, since thediluent absorbs the heat liberated during the reaction and thus preventsexcessive temperature rises.

Another mode of operation that may be used is the fluidized type whereinthe charge is passed upwardly through a bed of finely divided adsorbentmaterial, there by causing the particles to become motionalized andforming a fiuidlike mass. A portion of the adsorbent may be continuouslywithdrawn from the reaction zone, cooled, and returned thereto; thusproviding an efiicient method of removing the heat of reaction.

Instead of separately adding the peroxide catalyst to the reaction zone,I have found that it frequqently is more desirable and economical toform the catalyst in situ in the diluent and then charge the resultingsolution to the reaction zone together with the ethylene. Formation ofthe peroxide in the cycloparaflin diluent may be accomplished byauto-oxidation, i. e., by heating the hydrocarbon while air is bubbledthrough it, preferably in the presence of a trace of peroxide formed ina previous auto-oxidation. Alternatively, the air may be passed throughthe hydrocarbon in the presence of an oxidation catalyst such asmanganese stearate. In some cases it will be beneficial to add a minoramount of olefinic or cycloolefinic hydrocarbon to the cycloparafiinbefore passing air through it.

In the continuous methods of carrying out my process, the catalystpreferably is added continuously to the reaction zone, but, if desired,it may be added intermittently, particularly when a packing materialwhich retains catalyst is employed in the reactor.

The temperature employed in the process of this invention should be atleast as high as the initial decomposition temperature of the peroxideused as the catalyst. In the case of tertiary butyl perbenzoate, forexample, the decomposition temperature is approximately 115 C. ertemperatures may be employed but little advantage is gained if thetemperature is more than about 150 C. higher than the decompositiontemperature of the catalyst. The general efiect of increasing thetemperature is to accelerate the rate of reaction, but the increasedreaction rate is accompanied by a decrease in the molecular weight ofthe polymer. Thus by choosing a temperature within the indicated range,as well as by varying the proportion of ethylene to cycloparafiin,polymers varying from semi-solids to liquids may be obtained.

In contrast to many of the prior art processes that dealt with ethylenepolymerization, pressures as low as 15 atmospheres may be employed withgood results in my process. Pressures as high as 500 atmospheres may beused, but the preferred range is from about 30 to about atmospheres. Ingeneral, the molecular weight of my condensation product or polymerincreases with increasing pressure.

The concentration of catalyst utilizable in my process can vary over awide range. For reasons of economy, it generally is desirable to use lowconcentrations of catalysts such as from about 0.1% to about 4% of theethylene charge. Higher concentrations of catalyst result in lowermolecular weight products and if such products are desired they may beprepared by using catalyst concentrations up to 15% or more.

In batch operations and in flow operations that do not employ packingmaterials, the contact time should be in the range of from about 3minutes to about 6 hours. However, contact times of at least 10 minutesusually are preferred. In fixed bed operations the space velocity,defined as the volume of liquid charged per hour divided by thesuperficial volume of the packing, should be in the range of about 0.1to about 10.

The ratio of cycloparaffin diluent to ethylene charged to the reactionZone may vary over a relatively wide range. In general, the conversionof ethylene to polymer increases, but at a decreasing rate, as theweight ratio of diluent to ethylene is increased, and the averagemolecular weight of the product increases. A 1:1 ratio is satisfactory,but economic, operating, and product quality considerations may dictatethe use of higher or lower ratios.

The following examples are given to illustrate my invention but they arenot introduced with the intention of unduly limiting the generally broadscope of said invention. The experiments given under the examples werecarried out by heating the reactants in a glass liner in a rotatingautoclave for four hours. Unless otherwise noted, the charge was 3 gramsof peroxide, 50 grams of diluent, and 40 atmospheres of initial ethylenepressure, which is equivalent to approximately 40 grams of ethylene.

EXAMPLE I Efiect of impurities The data given below were obtained inexperiments conducted at C. using tertiary butyl perbenzoate as acatalyst.

ASTM Test Method Dl2730.

It can be seen that under these conditions of operation, no polymer wasobtained in the absence of a diluent or solvent. Also, it should benoted that substantially greater yields of a product with differentcharacteristics were obtained when using methylcyclohexane as comparedto the results obtained with the alcohol and aromatic solvent.

EXAMPLE II Effect of ethylene concentration Different concentrations ofethylene were obtained in the experiments shown below, by followingdifferent procedures in charging the autoclave. In Experiment 2,ethylene was passed into the autoclave, containing the diluent, to apressure of 40 atmospheres. Thereafter, the autoclave was rotated atroom temperature for minutes, during which time the pressure decreased.Ethylene was again added to the autoclave to once more bring thepressure up to 40 atmospheres. In Experiment 5, the autoclave wascharged to a pressure of 40 atmospheres, with no subsequent rotating ofthe autoclave or recharging with ethylene. Thus, although the initialpressure in each case was 40 atmospheres, there was considerably moreethylene in the autoclave in Experiment 2, due to solution in thediluent, than there was in Experiment 5. This is shown by the maximumpressures obtained in the two experiments and by a comparison of theyields.

1 Ethylene charged to pressure shown. Autoclave heated from 110115O.during four hours The foregoing data show that it is possible to alterthe character of the product by changing the ratio of ethylene todiluent.

EXAMPLE III Efiect of temperature The following data show the effect oftemperature upon the yield and quality of the polymer on condensationproduct. In each of the experiments the diluent was methylcyclohexane.

Experiment No 6 7 8 9 10 Temperature C 75 115 200 130 200 CatalystTertiary Di-Tertiary Butyl Perbenzoate Butyl Peroxide Product:

Weight,g o 29 16 4e 1s. Consistency Grease- Liquid. Grease- Liquid.

like. like.

It can be seen that increasing the temperature decreased the yield andmelting point of the polymer and that no product was obtained when thereaction temperature was lower than the decomposition temperature of thecatalyst. The liquid polymers produced in the two experiments wereunsaturated and had bromine numbers of 10.

EXAMPLE IV Efiect of impurities Two experiments were conducted in whicha 50/50 mixture of ethane and ethylene, initial pressure equal 40atmospheres, was contacted with 3 g. of tertiary butyl perbenzoate. Inthe first experiment, no cycloparaffin diluent was present; whereas inthe second, 50 g. of methylcyclohexane was present. In the firstexperiment only 4 g. of polymer was obtained; whereas in the second, 18g. was obtained.

From the foregoing data it can be seen that by the use of my inventionlong chain alkylcycloparafiins can be produced from ethylene andcycloparafilns at relatively mild operating conditions and with lowconsumptions of catalyst. It can further be seen that a variety ofproducts can be made and that these products possess valuable and usefulcharacteristics.

I claim as my invention:

1. A process for producing alkylcycloparatfins which comprises forming amixture consisting of ethylene, a cycloparaflin and an organic peroxidecatalyst, reacting the ethylene with the cycloparaflin by heating saidmixture at a pressure above about 15 atmospheres to a temperature atleast as high as the initial decomposition temperature of said catalyst,and recovering the resultant ethylenecycloparaflin reaction product.

2. The process of claim 1 further characterized in that saidcycloparaifin comprises a cyclohexane.

3. The process of claim 1 further characterized in that saidcycloparaflin comprises an alkylcyclohexane.

4. The process of claim 1 further characterized in that saidcycloparaflin comprises methylcyclohexane.

5. The process of claim 1 further characterized in that saidcycloparaflin comprises a cyclopentane.

6. The process of claim 1 further characterized in that saidcycloparafiin comprises an alkylcyclopentane.

7. The process of claim 1 further characterized in that saidcycloparaflin comprises methylcyclopentane.

8. The process of claim 1 further characterized in that saidcycloparatfin comprises decahydronaphthalene.

References Cited in the file of this patent UNITED STATES PATENTS2,402,137 Hanford, et al June 18, 1946 2,450,451 Schmerling Oct. 5, 19482,482,877 Schmerling Sept. 27, 1949

1. A PROCESS FOR PRODUCING ALKYLCYCLOPARAFFINS WHICH COMPRISES FORMING AMIXTURE CONSISTING OF ETHYLENE, A CYCLOPARAFFIN AND AN ORGANIC PEROXIDECATALYST, REACTING THE ETHYLENE WITH THE CYCLOPARAFFIN BY HEATING SAIDMIXTURE AT A PRESSURE ABOVE ABOUT 15 ATMOSPHERES TO A TEMPERATURE ATLEAST AS HIGH AS THE INITIAL DECOMPOSITION TEMPERATURE OF SAID CATALYST,AND RECOVERING THE RESULTANT ETHYLENECYCLOPARAFFIN REACTION PRODUCT.